Dual band receiver capability in portable frequency modulated (FM) radios provides the ability to receive a broader range of frequencies. An example of a dual band receiver would be one that operates at both very high frequencies (VHF: 140-170 MHz) and ultra high frequencies (UHF: 400-512 MHz). Currently, portable FM radios achieve dual band capability through the use of separate receiver circuits. The use of separate receiver circuits, however, entails additional circuitry such as a crystal filter, a mixer, a low noise amplifier, a pre-selector as well as the added expense of a dual band antenna. For many radio products, particularly those competing in the low cost consumer arena, this additional circuitry is simply not an option, and thus these radios have tended to remain single band radios.
Radio users would greatly appreciate a product that has dual band capability without the additional cost typically associated with creating a dual band receiver. The ability to receive certain VHF frequencies would be particularly beneficial to the UHF radio user. For example, the FCC has allocated certain frequencies for particular functions such as the VHF 162 MHz band which is strictly used as a receive frequency for weather broadcasts, the 157 MHz band which is strictly used for marine reports, and HAM bands. A UHF radio that could provide VHF features, such as weather broadcasts and/or marine reports, would be very beneficial for sports enthusiasts, construction crews, family members, and other users of UHF consumer products.
Accordingly, there is a need for a portable radio which provides dual band capability without the need for separate receivers, complex circuitry, and additional space.